Air conditioning system using well water as heat source

Abstract

To provide an air conditioning system having air conditioning means used as a base load and air conditioning means used as a support, both of which use well water as a heat source.SOLUTION: In addition to first air conditioning means 1, which includes a first heat exchanger 30 on a heat source side immersed in a well water storage tank 20 and a second heat exchanger 50 on a user side installed indoors, and a heat pump 40 that transfers heat between the first heat exchanger 30 and the second heat exchanger 50, an air conditioning system also comprises second air conditioning means 2, which is installed in the same room as the second heat exchanger 50 and has a third heat exchanger 60 through which well water W flows as a heat medium. Either the first air conditioning means 1 or the second air conditioning means 2 is used as a base load, and the other air conditioning means is used as a support.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system that uses well water as a heat source, and more particularly to an air conditioning system that has an air conditioning means used as a base load and an air conditioning means used as a support, both of which use well water as a heat source. [Background technology]

[0002] The temperature of well water (pumped up groundwater) varies slightly depending on the region, but in the Kanto Plain, Nobi Plain, and Osaka Plain, the water temperature is said to be 16-18°C, with an annual temperature difference of less than 1°C. Fig. 4 shows an example of an air conditioning system that uses well water with this stable temperature as the heat source for a heat pump.

[0003] This air conditioning system is an open-loop system, and its basic configuration includes a storage tank 20, a first heat exchanger 30 on the heat source side (primary side), a heat pump 40, and a second heat exchanger 50 on the user side (secondary side).

[0004] The reservoir 20 stores well water (groundwater) W pumped up from underground by a pumping pipe 10 having a pumping pump 11. The reservoir 20 is an overflow type, and is always kept at a constant water level.

[0005] The first heat exchanger 30 is immersed in the well water W of the storage tank 20. A heat medium such as water or brine is sealed inside the first heat exchanger 30. A heat medium circulation pipe 31 including an outward pipe 31a, a return pipe 31b, and a circulation pump 32 is connected to the first heat exchanger 30, and the heat medium circulates while exchanging heat with the well water W.

[0006] The heat pump 40 includes a compressor, a four-way valve, an expansion valve, etc. (not shown), a first heat exchanger 41 on the primary side, and a second heat exchanger 42 on the secondary side. These components are connected via refrigerant piping, and the refrigerant circulates when the compressor is operating. The four-way valve can be switched between a heating cycle and a cooling cycle.

[0007] The second heat exchanger 50 is an air-to-cooling indoor heat exchanger placed indoors in a building (including a greenhouse cultivation facility, etc.) H, and has a predetermined heat medium sealed inside. A heat medium circulation pipe 51 including a circulation pump 52 is connected to the second heat exchanger 50. In many cases, a fan coil unit is used for the second heat exchanger 50.

[0008] The first heat exchanger 30 is thermally connected to a first heat exchange section 41 of the heat pump 40 via a heat medium circulation pipe 31. The second heat exchanger 50 is thermally connected to a second heat exchange section 42 of the heat pump 40 via a heat medium circulation pipe 51.

[0009] By switching the four-way valve, the heat pump 40 is operated so that during the heating cycle, the first heat exchange section 41 side acts as an evaporator and the second heat exchange section 42 side acts as a condenser, and during the cooling cycle, the first heat exchange section 41 side acts as a condenser and the second heat exchange section 42 side acts as an evaporator.

[0010] In addition, when the unit is used exclusively for heating, the refrigerant flows from the compressor → second heat exchange section 42 → expansion valve → first heat exchange section 41 → compressor, and the unit is operated so that the second heat exchange section 42 side always functions as a condenser and the first heat exchange section 41 side always functions as an evaporator.

[0011] For example, in greenhouse cultivation facilities, the above-mentioned heat pump air conditioning system is used as a base load, and an air conditioning system equipped with an auxiliary heat source (support heat source) 60 such as a boiler as a hybrid system is known (see Non-Patent Document 1).

[0012] However, this type of auxiliary heat source 60 uses fossil fuels such as petroleum, which is undesirable from both an environmental and cost perspective. [Prior art documents] [Patent documents]

[0013] [Non-Patent Document 1] Hokkaido University Environmental Systems Engineering Laboratory, "Ground Source Heat Pump System (Revised 2nd Edition)" Figure 7.2(b) System Combined with Other Heat Sources, Ohmsha Publishing Summary of the Invention [Problem to be solved by the invention]

[0014] Therefore, an object of the present invention is to provide an air conditioning system having an air conditioning means used as a base load and an air conditioning means used as a support, both of which use well water as a heat source. [Means for solving the problem]

[0015] In order to solve the above problems, the air conditioning system of the present invention is characterized in that it comprises a first air conditioning means including a first heat exchanger on the heat source side immersed in a well water storage tank that stores well water, a second heat exchanger on the user side installed indoors, and a heat pump that transfers heat between the first heat exchanger and the second heat exchanger, as well as a second air conditioning means installed in the same room as the second heat exchanger and having a third heat exchanger through which well water flows as a heat medium, and in that either the first air conditioning means or the second air conditioning means is used as a base load, and the other air conditioning means is used as a support.

[0016] In addition, the air conditioning system of the present invention is characterized in that, in addition to a first air conditioning means including a first heat exchanger on the heat source side immersed in a well water storage tank that stores well water and a second heat exchanger on the user side installed indoors, and a heat pump that transfers heat between the first heat exchanger and the second heat exchanger, it also includes a second air conditioning means having a third heat exchanger installed in the same room as the second heat exchanger, the first heat exchanger and the third heat exchanger are connected via a heat medium forward pipe and a return pipe, a part of the return pipe includes a heat source side heat exchange section within the heat pump, and either the first air conditioning means or the second air conditioning means is used as a base load, and the other air conditioning means is used as a support air conditioning means.

[0017] According to a preferred embodiment of the present invention, the second air conditioning means is used for base load purposes, and fan coil units are used for the second heat exchanger and the third heat exchanger. [Effects of the Invention]

[0018] According to the present invention, there is provided an air conditioning system having air conditioning means used as a base load and air conditioning means used as a support, both of which use well water as a heat source. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing an air conditioning system according to a first embodiment of the present invention. [Figure 2] 1 is a perspective view showing a planar heat exchanger preferably used in the present invention. [Figure 3] FIG. 5 is a schematic diagram showing an air conditioning system according to a second embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram showing a conventional hybrid air conditioning system. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, a first embodiment and a second embodiment of the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited to these embodiments.

[0021] 1, the air conditioning system according to the first embodiment includes two air conditioning means: a first air conditioning means 1 and a second air conditioning means 2. Both the first air conditioning means 1 and the second air conditioning means 2 use well water (pumped up groundwater) as a heat source.

[0022] As explained above in Figure 4, the first air conditioning means 1 basically comprises a storage tank 20, a first heat exchanger 30 on the heat source side (primary side), a heat pump 40, and a second heat exchanger 50 on the utilization side (secondary side).

[0023] The reservoir 20 stores well water (groundwater) W pumped up from underground by a pumping pipe 10 having a pumping pump 11. The reservoir 20 may be of an overflow type so that the water level is always kept constant.

[0024] The first heat exchanger 30 is immersed in the well water W of the storage tank 20. A heat medium such as water or brine is sealed inside the first heat exchanger 30. A heat medium circulation pipe 31 including an outward pipe 31a, a return pipe 31b, and a circulation pump 32 is connected to the first heat exchanger 30, and the heat medium circulates while exchanging heat with the well water W.

[0025] Referring to FIG. 2, the first heat exchanger 30 preferably employs a planar heat exchanger 310 having a plurality of heat exchange tubes 313 connected in parallel between a first end tube 311 on the heat medium inlet side and a second end tube 312 on the heat medium outlet side.

[0026] Each heat exchange tube 313 is connected to the first end pipe 311 and the second end pipe 312. In this embodiment, the heat medium is supplied from the return pipe 31b to the first end pipe 311 by operating the circulation pump 32, flows through each heat exchange tube 313 toward the second end pipe 312, exchanges heat with the well water W, and flows from the second end pipe 312 toward the outward pipe 31a.

[0027] The heat exchange tubes 313 may be flexible synthetic resin tubes, such as polyethylene tubes. As an example, the heat exchange tubes 313 are φ6 mm x 3.8 m long tubes, with 117 tubes arranged parallel to each other at equal intervals between the end tubes 311 and 312 by beam members 314. Because the planar heat exchanger 31 appears to be a single sheet, it is sometimes called a heat exchange sheet or sheet-like heat exchanger. The planar heat exchanger 31 can also be rolled up.

[0028] The heat pump 40 includes a compressor, a four-way valve, an expansion valve, etc. (not shown), a first heat exchanger 41 on the primary side, and a second heat exchanger 42 on the secondary side. These components are connected via refrigerant piping, and the refrigerant circulates when the compressor is operating. The four-way valve can be switched between a heating cycle and a cooling cycle.

[0029] The second heat exchanger 50 is an air-cooled indoor heat exchanger placed indoors in a building (including a greenhouse cultivation facility) H, and has a predetermined heat medium sealed inside. A heat medium circulation pipe 51 including a circulation pump 52 is connected to the second heat exchanger 50. In this embodiment, a fan coil unit is used for the second heat exchanger 50.

[0030] The first heat exchanger 30 is thermally connected to a first heat exchange section 41 of the heat pump 40 via a heat medium circulation pipe 31. The second heat exchanger 50 is thermally connected to a second heat exchange section 42 of the heat pump 40 via a heat medium circulation pipe 51.

[0031] By switching the four-way valve, the heat pump 40 is operated so that during the heating cycle, the first heat exchange section 41 side acts as an evaporator and the second heat exchange section 42 side acts as a condenser, and during the cooling cycle, the first heat exchange section 41 side acts as a condenser and the second heat exchange section 42 side acts as an evaporator.

[0032] In the case of a device used only for heating, the refrigerant flows from the compressor → second heat exchange section 42 → expansion valve → first heat exchange section 41 → compressor, and the device is operated so that the second heat exchange section 42 side always functions as a condenser and the first heat exchange section 41 side always functions as an evaporator.

[0033] In addition, in the case of a dedicated cooling unit, the refrigerant flows from the compressor → first heat exchange section 41 → expansion valve → second heat exchange section 42 → compressor, and the unit is operated so that the first heat exchange section 41 side always functions as a condenser and the second heat exchange section 42 side always functions as an evaporator.

[0034] The second air conditioning means 2 includes a third heat exchanger 60. The third heat exchanger 60 is installed in the same room as the second heat exchanger 50, and well water flows through the third heat exchanger 60 as a heat medium. In this embodiment, a fan coil unit is used for the third heat exchanger 60.

[0035] A supply pipe 61 for well water W and a drain pipe 62 are connected to the third heat exchanger 60. In this embodiment, the supply pipe 61 branches off from the well water pumping pipe 10 used in the first air conditioning means 1, but a well water pumping means dedicated to the second air conditioning means 2 may also be provided.

[0036] A flow control valve 63 with a water stop function is provided in the well water supply pipe 61. Wastewater that has completed its work in the third heat exchanger 60 flows into the drain pipe 62, and the wastewater may be returned to the storage tank 20 or may be used as agricultural water, industrial water, etc.

[0037] Since the temperature of the well water W is 16 to 18°C, with an annual temperature difference of less than 1°C, the second air conditioning means 2 can be used as a base load, i.e., by continuously flowing well water W through the third heat exchanger 60 regardless of the time of day or night, the temperature inside the conditioned room can be maintained at around 16 to 18°C.

[0038] When the second air conditioning means 2 alone is not sufficient for heating in winter or cooling in summer, the first air conditioning means 1 having the heat pump 40 can be used in a supporting (auxiliary) manner. Conversely, the first air conditioning means 1 can be used as a base load, and the second air conditioning means 2 can be used in a supporting manner.

[0039] Although not shown, it is preferable to use a temperature regulator having a room temperature sensor to control the flow rate adjustment valve 63 and the heat pump 40 so that the room temperature reaches the set temperature.

[0040] Next, a second embodiment will be described with reference to Fig. 3. In this second embodiment, the wastewater that has completed its work in the second air conditioning means 2 is used on the heat source side of the first air conditioning means 1.

[0041] Therefore, the first heat exchanger 30 and the third heat exchanger 60 are connected via a heat medium circulation pipe 31 including an outward pipe 31a, a return pipe 31b, and a circulation pump 32, and a portion of the return pipe 31b is made into a heat exchange section included in the first heat exchange section 41 of the heat pump 40.

[0042] According to this, the heat medium that has exchanged heat with well water W in the first heat exchanger 30 is sent by the circulation pump 32 through the outward pipe 31a to the third heat exchanger 60, where it exchanges heat with indoor air, and on the way back to the first heat exchanger 30 through the return pipe 31b, the heat medium is subjected to heat absorption or heat release in the first heat exchange section 41 of the heat pump 40.

[0043] In this second embodiment, the third heat exchanger 60 can also be used as a base load by operating the circulation pump 32, for example, day and night, to continuously flow the heat medium that has been heat exchanged with the well water W in the first heat exchanger 30 into the third heat exchanger 60.

[0044] Although not shown, a fourth air-cooled heat exchanger can be installed under the floor of building H, and in either the first or second embodiment, a floor heating and cooling system can be constructed by flowing the heat medium of the first air conditioning means 1 and / or the second air conditioning means 2 through the fourth heat exchanger.

[0045] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the description of the above embodiments. Modifications or improvements made to the above embodiments by those skilled in the art are also included in the technical scope of the present invention. [Explanation of symbols]

[0046] 1 First air conditioning means 2 Second air conditioning means 10. Lifting pipe 11 Water pump 20 Well water storage tank 30 1st heat exchanger 31,51 Heat transfer medium circulation pipe 40 Heat Pump 41 First heat exchange section on the heat source side 42 Second heat exchange section on the user side 50 Second heat exchanger 60 Third heat exchanger

Claims

1. In addition to a first air conditioning means including a first heat exchanger on the heat source side immersed in a well water storage tank that stores well water, a second heat exchanger on the user side installed indoors, and a heat pump that transfers heat between the first heat exchanger and the second heat exchanger, An air conditioning system that uses well water as a heat source, characterized in that it is equipped with a second air conditioning means installed in the same room as the second heat exchanger and having a third heat exchanger through which well water flows as a heat medium, and in that either the first air conditioning means or the second air conditioning means is used as a base load and the other air conditioning means is used as a support air conditioning means.

2. An air conditioning system that uses well water as a heat source, characterized in that it is equipped with a first air conditioning means including a first heat exchanger on the heat source side immersed in a well water storage tank that stores well water, a second heat exchanger on the user side installed indoors, and a heat pump that transfers heat between the first heat exchanger and the second heat exchanger, as well as a second air conditioning means having a third heat exchanger installed in the same room as the second heat exchanger, the first heat exchanger and the third heat exchanger are connected via a heat medium forward pipe and a return pipe, and a heat source side heat exchange section within the heat pump is included in a part of the return pipe, and either the first air conditioning means or the second air conditioning means is used as a base load, and the other air conditioning means is used as a support air conditioning means.

3. 3. The air conditioning system using well water as a heat source according to claim 1, wherein the second air conditioning means is used as a base load.

4. 3. The air conditioning system using well water as a heat source according to claim 1, wherein fan coil units are used for the second heat exchanger and the third heat exchanger.

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